Dental flask



Nov. 6 1923, 1,473,276

\ M. F. BURNS I DENTAL FLASK Filed March 24, 1922 Patented Nov. 6, i923.

MARTIN E. BURNS, F ASTORIA, NEW YORK.

iguana DENTAL FLASK.

Application filed March 24, 1922. Serial No. 546,304.

To aZZ whom it may concern.

Be it known that L MARTIN F. BURNS, a citizen of the United States, and a resident of Astoria, county of Queens, and State of New York, have invented certain new and useful Improvements in Dental Flasks, of which the following is a specification.

This invention relates to dental apparatus and more particularly to dental flasks of the type used by dentists in casting plates, bridges, inlays and other restorations.

In casting a plate, bridge or other restora tion a dentist first makes a pattern in wax of the article to be cast. The pattern is then invested in an initially plastic and quick hardening composition. When the investment is dry or has set the wax is melted out or otherwise dissipated, the cavity is lilled with molten metal. The casting is then allowed to cooland is preferably cooled slowly to prevent warping or distortion. When warping or distortion takes place it is neces sary to swag'e the casting to its proper shape.

It is very desirable that the rate of heating or cooling the investment and the parts contained thereby be regulated as different classes of work require different treatment.

This invention has for its object, therefore, to provide means in apparatus of the class described for regulating the heating or I cooling of the investment and parts contained thereby.

Another object of the invention is to provide a construction by means of which the quantity of investment used will be conserved.

Further objects of the invention will appear from the following description taken in connection with the drawings which form a part of this application and in which,

Fig. 1 is an elevation, partly in section, showing a dental flask constructed in accordance with my invention and with the parts in assembled position.

Fig. 2 is a transverse sectional elevation taken substantially on line 2-2 of Fig. 1.

Fig. 3 is a bottom plan viewof the construction shown in Fig. 1 with the investment holder and a receptacle in one position of relative adjustment and Figs. 4 and 5 are views similar to Fig. 3 I

but showing the parts in their positions of adj ustment.

The invention may be briefly described as including a receptacle and an investment holder so relatively constructed and arranged that these parts may be relatively adjusted to regulate the rateof heatingor cooling of the investment holder and parts contained thereby. I

The receptacle is preferably cylindrical in shape and has an imperforate wall, an open upper end 11 and a lower and partially closed by the bottom 12. The bottom 12 is formed by an annular inwardly extending flange and this bottom has an oblong opening 13 formed therein. The side edges 14: of the opening are straight and the end edges 15 are curved on an are having the axis of the cylindrical receptacle shell as its center. I

The investment holder comprisesa pair of vertical, substantially parallel, spaced walls 16 connected at their upper-and lower edges by strips or webs 17. 'At its upper end the investment holder has formed thereon laterally extending flangeslS conforming at their outer peripheral edges in shape to the inner peripheral wall of the receptacle 10. t will be seen fIOHltllG showing in Fig. 1 that air spaces 19 are formed at each sideof the investment holder and between the walls 16 of the holder and the wall of the receptacle 10.

A cover 20 is provided for the upper end of the receptacle and this cover has formed therein countersunk openings 21 through which the investment projects and by means of which the investment secures the-cover to the receptacle. The cover 20 has also formed thereon an upwardly-extending cylindrical. flange 22. As pointed outin the early part of thespecification, afterthewax pattern has been embedded in the investment, heat is applied to the apparatus and. this heat will cause the wax to dissipate thereby leaving a cavity in theinvestment. Gates or sprues'are formed in the investment for conducting molten metal to the cavity left by the wax and one method of filling the cavity is carried out by melting the metal by a blow torch whereupon it flows into the cavity and by applying air pressure to the apparatus to force the metal to entirely fill the mold or cavity;

For diflerent classes of work the heating and cooling must be accomplished at difierentrates and in order to provide for this the receptacle and investment holder have been designed in the particular manner;

, above described. In Fig. 3 these parts are shown in the position in which air is excluded from circulating to or from the spaces 19 between the walls 16 of the investment holder and the receptacle. It should be borne in mind that the investment holder is filled between the walls 16 with the investment.

In'Fig. 4 the holder and receptacle are adjusted toadmit orpermit the exit of a maximum uantity {of air to and from the spaces 19. the parts in this position in heating, the heat will be very quickly applied and in cooling the cooling effect will take p ac ap dl In Fig. 5' the parts are shown 1n another position of adjustment where the spaces 19 p are p'ai tially open for the circulation of the air or the admission of a flame. v

to clot n a still slower cooling e'fiecitl have shown in Fig. 1 means for sea ing the 're ep'te le thereby pp the rate 'of means comprises a pair of caps BOand 31 having lining material 32 therein and adapted to fit respectively over 'thehottom oi the receptacle and over h t r "9 the f ang 22- is believed that the operation and method of using the various parts of the apparatus will be clear from the foregoing 'escription without a further detailed statemeat thereofi From the foregoing specification it will be e ident that mean a been provided for regula ng t rough a Wid range the rate Of heating or cooling of the investment holder and'the parts contained thereby. It will also be noted that the investment holder is so en'struct'ed that a minimum amount of investment is necessary. 7

Although one specific embodiment of the invention has been illustrated and described it will be. understood that the invention is capable of modification and that changes in the construction and in the arrangement of the various cooperating parts may be made without departing from the spirit or scope of the invention as expressed in the followins leim I What I c i 1. combination, a receptacle provided with a hottom having an angular opening therein and "an investment holder adapted to be positioned in said receptacle comprising a pair of substantially vertical walls spaced apart a distance less than the maxi- Width of the Opening in the bottom of the receptacle.

2. In inatiofn, a receptacle provided h 'nfg an angular opening tment holder adapted to ed in said eceptacl comprising tially vertical, parallel a distance less than the a, o; v we is spaced apart circulation of air and further retarding the maximum width of the opening in the bottom of the receptacle. 7

8. in combination, a receptacle provided with a bottom having an oblong opening therein and an investment holder adapted to be positioned in said receptacle comprising a pair of substantially vertical Walls spaced apart a distance less than the maximum width of the opening in the bottom of the receptacle.

4. In combination, a receptacle an investment holder adapted to be positioned therein with its walls spaced from the receptacle wall and means including the receptacle and holder for regulating the air circulation to the spaces at the sides of the holder.

5. In combination, a receptacle having an apertured bottom, an investment holder adapted to be positioned therein with its walls spaced from the receptacle wall and means including the receptacle and holder for regulating the air circulation to the spaces at thesides of the holder.

6. In combination, a receptacle having a bottom flange forming an oblong opening, an

investment holder adapted to fit in the re ceptacle and having a pair of substantially vertical, spaced, parallel, walls, the opening in the receptacle bottom being longer than the distance between the spaced investment holder walls.

7. In combination, a receptacle having a bottom flange forming an oblong opening having straight sides, an investment holder adapted to lit in the receptacle and having a pair of substantially vertical, spaced, parallel, walls, the opening in the receptacle bottom being longer than the-distance between. the spaced investment holder walls.

8. In combination, a receptacle, an investment holderadapted to be positioned therein with its valls spaced from the receptacle wall and means including the receptacle and holder for controlling the communication between the spaces at the sides of the holder and the air surrounding the receptacle.

9. In combination, a receptacle having an apertured bottom, an investment holder adapted to be positioned therein with its walls spaced from the receptacle wall and means including the receptacle and holder for varying the. openings between the spaces at the sides of the holder and theair surrounding the receptacle.

10.. In combination, a'receptaclc provided MARTIN r. snares. 

